FAQ00653 of Temperature Controllers FAQ

Temperature control over a controlled object would be difficult if heating was the only type of control available, so cooling control was also added. Two control outputs (one for heating and one for cooling) can be provided by one Temperature Controller.

Heating and Cooling Outputs

Set cooling control (direct operation).

Change the direct/reverse operation setting to direct operation.

For example, if you set the temperature (e.g., to 30 °C), the control output will turn ON when the temperature is above the set temperature and will turn OFF when it's below the set temperature.

If the temperature rises above the set temperature again, the output will turn ON again.

The point at which the output turns ON is also affected by the hysteresis setting.